Managed care and reductions in government spending have placed great pressure on providers, payers, and researchers to demonstrate the cost-effectiveness and cost-benefits of drug treatment services. As a first step in these economic evaluations, the costs of specific treatment services must be estimated. Although much previous work has estimated drug treatment costs, only a very limited number of service cost estimates exist, and no study has evaluated the effect of alternative data collection methods on estimated service costs. Furthermore, no previous work has attempted to estimate the burden of collecting service cost data. Our proposed analysis evaluates three alternative methods for estimating service-level costs in methadone treatment programs. These three methods differ in how they collect staff time allocation across treatment services. The three alternative data collection methods are (1) surveying the clinic director (key informant), (2) surveying the clinic staff (staff informants), and (3) staff diaries for 1 week. Our analysis will assess the extent to which differences in the method used to collect the staff time allocation across alternative treatment services contribute to differences in service cost estimates. In addition, as part of the service cost evaluation, we will also estimate the costs of collecting the staff time allocation data for each of the three data collection methods. Implementation of these three estimation methods will occur in a sample of methadone clinics that were part of CSAT's Evaluation of the Methadone/LAAM Treatment Accreditation Project. To accomplish our research objectives, the specific aims of our analysis are to (1) develop a revised taxonomy of methadone treatment services and job types, (2) estimate the costs of specific treatment services, and (3) evaluate the sources of service cost variation. The research team has a strong track record estimating the costs of treatment, and extensive knowledge and insights into the fundamental issues involved in this research. At the conclusion of our proposed research project, we will understand the extent to which differences in collecting staff labor time affect estimates of treatment service cost, and we will have developed and implemented a revised service cost estimation methodology that will be applicable to all drug treatment modalities.